Estoque de carbono, nitrogênio, frações e modelagem damatéria orgânica de latossolo amarelo do cerrado

• Autor(a) principal: Costa, Adilson Alves
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/26141
• topic: Infravermelho; Century; Fracionamento; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

Accordingly, this study was performed with the objective to evaluate changes caused by different types of land use on the carbon and nitrogen stocks as well as to study, by infrared Spectroscopy Fourier possible alterations of the structure chemical soil samples and light organic material, and to adapt the model Century4. 5 to simulate stocks of C and N in the soil of the soil and climatic conditions cerrado. The survey was conducted in the municipality of Luis Eduardo Magalhães, Western Bahia, a city in full agricultural expansion, especially with soybean, corn, cotton and most recently, eucalyptus. In this sense, we selected four areas in different forms of land use, and, areas under conventional planting area under tillage, area under pasture and area under eucalyptus planting and, as reference, an area under native vegetation cerradão. The soil was classified as Oxisol, medium texture and poor in organic matter. In the various forms of land use five profiles were opened which is collected soil samples at depths of 0-5 cm, 5-10 cm, 10-15 cm, 15- 20 cm, 20-30 cm, 30-40 cm and 40-60 cm. They evaluated the content and inventory of C and N soil, particle size, bulk density, chemical and physical fractionation, carbon management index, identification of functional groups by spectroscopic technique infrared, and also adapted to the Century4 model. 5 through changes in its parameters according to the characteristics of the soil and climatic cerrado, to simulate the C stocks and N. the area under increased till the C content in the surface depth of 10 cm, but not their inventories exceeded 5 cm, compared to other forms of land use. The cultivation of pasture contributed to recover the C stocks up to 40 cm. For total N, considering a depth of 60 cm, the forms of use as soil tillage, and conventional grazing, their values decreased up to 41%, 59% and 67%, respectively, compared to the area under native cerrado vegetation. The conventional farming, grazing and direct favored a carbon enrichment in the fulvic acid fraction at a depth of 5-10 cm, however, only the cultivation of pasture and tillage increased in the 15- 20 cm. With respect to carbon management index (CMI) and eucalyptus grazing stood in relation to other forms of land use, even when compared to area under native cerrado vegetation at all depths measured. In all areas we verified the presence of aliphatic, aromatic, -OH, carboxyl and carbonyl. However, there was a decrease in the degree of resistance to light decomposition of organic matter samples (OMS) on the area under the tillage depth of 20 cm. The Century4.5 error model presented below 1% and 4% for the stocks of C and N, respectively, in the native vegetation areas under cultivation eucalyptus, setting data for the simulation. Replacement of the native vegetation by eucalyptus over time is able to increase the carbon and nitrogen stocks in the soil.